In a client-server system including a plurality of servers, a request which is given from a client to a server which is an arithmetic device for processing a job is allocated to one of the plurality of servers by a load balancer that functions as load distribution means. That is, a job which has been designated by a user of the client is allocated to one of the servers. Job allocation is performed in accordance with a previously set load distribution algorithm. The load distribution algorithms includes a round robin algorithm in which a server to which a job is to be allocated is selected in order, an algorithm in which a server which has the smallest number of in-process connections is selected, and an algorithm in which a server which responds first is selected.
In various systems including the client-server system, a reduction of power consumption is now being promoted. In order to attain power saving, for example, such a technique is proposed that only when load is lower than a threshold value in a computer system including a plurality of central processing units (CPUs), a CPU which is low in throughput but is low in power consumption is selected to be used. In addition, such a technique is also proposed that a task is scheduled to two processors of different power efficiencies so as to minimize the power consumption.